The present invention relates to an electronic keyboard musical instrument, and in particular to a capture system for such an instrument wherein there are fewer tone generator-keyers than keys or pedals, and each keyer is capable of capturing the data of any of the keys or pedals and controlling a tone generator to produce a corresponding tone.
An important aspect of organs and other electronic musical instruments, other than very small instruments with a very limited pedalboard or no pedalboard at all, is the production of pedal tones. In many smaller prior art organs, the pedalboard is monophonic with a priority system between the switches operated by the pedals so that only one switch is enabled at any time and the keyer system is capable of producing only one tone at a time. Because of the type of music often played on organs of this type, a monophonic pedal system is usually quite adequate.
In larger organs, such as large theater organs and institutional organs of the type used in churches, the performers generally possess a higher degree of skill, and the music written for such organs is much more complex. In such music, it is often necessary to play more than one pedal at a time so that a monophonic pedal system is not at all satisfactory. In most organs of this size, the pedalboard comprises thirty-two pedals, and thirty-two keyer units are required, thereby increasing the cost of the instrument, and in some cases prohibiting the addition of other features because of cost limitations. Such a system is quite redundant, however, because normally no more than two pedals are played at any given time so that much of the keyer system is inactive.
For many years now, capture keyer-tone generator systems have been utilized wherein there are less keyer-tone generators than keys to be played, and each keyer-tone generator is capable of producing a tone selected by any one of the keys or pedals to which it is assigned. This permits polyphonic playing without the necessity for having large banks of keyers, but has the drawback that many systems were often complicated and required a substantial amount of logic or even a microprocessor to capture and release the keyers in the proper manner. In many cases, it was necessary to utilize sophisticated memory addressing logic to determine which note a tone generator had captured and which tone generators were available for further assignment. Furthermore, due to the differences of processing the keyboard data in a capture keyer system as opposed to a more conventional keyer bank system, it was difficult to implement capture layer technology into existing organs without substantial modification.